sched: programmable: Add helpers to set tag of task or task_group

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5KUFB


CVE: NA

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Add helper function bpf_sched_set_tg_tag() and
bpf_sched_set_task_tag() to set tag for task group or task.

They can not be call when rq->lock has been held.

The use case is that the other kernel subsystems,
such as the network, can use it to mark key tasks.

Signed-off-by: Ren Zhijie <renzhijie2@huawei.com>
Signed-off-by: Hui Tang <tanghui20@huawei.com>